<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../vue.js"></script>
</head>

<body>
  <div id="app">
    <h1>{{msg}}</h1>
    <button @click="isHot=!isHot">改变天气</button>
    <p>今日天气</p>
    <!-- 
      v-else指令是与v-if指令配合使用的
      注意的是必须紧邻 v-if指令
     -->
    <span v-if='isHot'>热</span>
    <!-- <br> -->
    <span v-else>冷</span>
  </div>
  <script>
    Vue.config.productionTip = false;
    const vm = new Vue({
      el: "#app",
      data() {
        return {
          msg: "hello vue!",
          isHot: true
        }
      },
      methods: {}
    })
  </script>
</body>

</html>